Process Control Equipment in Food Industry

  1. Introduction:

Process control equipment in the food industry are the types of equipment that measure the variables of a technical process, direct the process according to control signals from the process computer system, and provides appropriate signal transformation. Examples of process control equipment include actuators, sensors, transducers, etc.

These are the equipment used to ensure that food processing equipment operates correctly and the processing stages are continued as specified SOP.

These are equipment, that can be used

    • to analyze ingredients and machines,
    • allowing manufacturers to perform and duplicate processing procedures.
    • monitor existing systems and machinery, such as logging data during product testing or quantifying typical performance statistics.

Control equipment’s are particularly crucial during food production, as minor changes in cooking temperature, ingredient ratios, and operation times can lead to drastic changes in the finished product. 

  1. Objective:

The main objective to implement control equipment’s in the food industry is to improve the economics of the process by achieving the following objectives: 

    • Reduce energy consumption and increase versatility
    • Enable cost-effective operation of the manufacturing process
    • Reduce the air consumption of pneumatically operated valves
  1. Sensors:

In the food industry sensors are designed with process connections for clamping directly onto the process. They have a high mechanical strength to withstand the temperature and pressure associated with food production. The use of sensors to monitor temperature throughout the production process helps to ensure an optimum final product and assures food safety.

3.1 Sanitary Sensor:

Hygienic Pressure Transmitters are used in food & dairy application mainly with strong features like high-performance, long-term stability, high performance of temperature characteristics, etc. To accomplish these objectives many types of sanitary sensors are used in the food industry. Few are listed below:

        • Hygienic Adapter System (Fluid less Type): This system composes of replaceable adapters (16 adapters in total) with the hygienic function of pressure detection. fluid less type’s pressure sensor doesn’t need liquid such as silicon oil. It adapts duplex stainless steel as a sensor material. This duplex stainless-steel material has both high corrosion resistance and high tension.

        • Digital Remote Sensor (DRS): Transmitter connects two pressure sensors, master (high-pressure side) and slave (a low-pressure side) in a remote location, with DRS dedicated communication cable to measure differential pressure. These are suitable for various kinds of pressure measurement.

        • Differential/gauge pressure diaphragm seal: Diaphragm Seal System consists of differential pressure or gauge pressure transmitter with one or two diaphragm seals.  Suitable for various kinds of pressure measurement.

        • Distributed Temperature Sensor: These sensor is capable of intelligently monitoring temperature distribution up to 50 km in the lengthways direction in real-time with the help of a fiber optic sensor cable. This helps achieve fire detection, fire prevention, and preventive maintenance of equipment over a wide area which has up till now been difficult with thermocouples, resistance temperature detectors, or radiation thermometers. DTSX supports the HSE (Health, Safety, and Environment) plus the maintenance of plants and the social infrastructure, and aids safe operation.

When a large-scale fire or equipment failure causes the production line to stop, the damage is not limited to just customers’ assets or loss of revenue opportunity, but the supply chain is also affected. The economic and social loss is immeasurable. DTSX can precisely identify abnormally hot locations as a fiber optic sensor cable is installed along the length of the measurement target. This enables a quick initial response for safety, which ensures that the operation of the plant and social infrastructure is maintained, and the customers’ assets and social credibility are protected.

        • Tunable Diode Laser Spectrometers (TDLS):

It allows real-time gas analysis to increase efficiency, safety, quality, and environmental compliance. The non-contacting sensor allows measurement under severe conditions, such as high temperature, high pressure, corrosive/abrasive conditions, high dust concentration, etc. Maintenance can also be performed without taking the process offline because the TDLS is isolated from the process. The TDLS is a robust process analyzer that contributes to stable and efficient operation.

        • Sushi Sensor:

To improve the availability ratio and profitability of plants, timely identification of health conditions and efficient maintenance of aged equipment are required. Various sensing technologies are needed to monitor conditions and maintain diverse equipment. To maintain equipment distributed across a plant efficiently with limited man-hours, quantification of measurement data and automated data acquisition and storage systems are required Sushi Sensor measures vibration, temperature, and pressure as data for maintaining equipment.

        • Level sensor:

level sensors are used for in-line measurement and control of the food processing operation. Typically, they may be used to monitor temperature and liquid levels rates, acid/alkali inputs, and gas flow. For example, a level sensor is used to determine specific volumes of liquid dispensed during the cooking phase, too much or too little may mean the product is spoiled. So, to take care of this level sensors are used in the food industry.


        • Coriolis Mass Flowmeters: 

Coriolis mass flow meter, which is widely considered the most accurate type of mass flow meter and is widely used in industrial applications for accurate measurement. Coriolis flowmeters feature instrumentation that function on the principles of the Coriolis effect – a notable (and strange) phenomenon whereby a mass moving in a rotating system experiences a force acting perpendicular to the direction of motion and the axis of rotation.

Application of this includes Batching, Dosing, Blending, Chemical injection, High-pressure gases, Liquid and gas low flow measurement, Precision coatings, R&D laboratory, Vacuum thin film coating, etc.

Typical Food Sensor Applications: 

      • Storage vessels – pumps and valves
      • Food processing monitoring systems, alarms, and alerts
      • Water purification
      • Liquid level sensing for industrial food processing operations
      • Cryogenic fast freeze technologies
      • Food test laboratories
      • Liquid gas storage
      • Transport
      • Liquid dispensing
      • Solvent and chemical control 


  1. Actuators:

Efficient food processing and packaging operations call for high-level robust technologies that are durable, precise, and safe for food. Various food industry procedures including cutting and slicing of raw materials and filling beverages, which need to be done systematically, without any contamination. To fulfill these demands, actuators are used at a high speed and with maximum efficiency.

An actuator is a device that produces a motion by converting energy and signals going into the system. The motion it produces can be either rotary or linear. Linear actuators, as the name implies, produce linear motion. This means that linear actuators can move forward or backward on a set linear plane – a set distance they can travel in either direction before they must stop. Rotary actuators on the other hand produce rotary motion, meaning that the actuator revolves on a circular plane.

Linear or rotary actuators are available in various forms depending on the power-supply source.  The actuator could be electrical, pneumatic, or hydraulic. The choice of actuator type used will most likely depend on the application and industry-specific requirements. For example, the natural choice for the food industry would be electrical actuators.

4.1 Electrical Actuators:

Electric Linear Actuators are a crucial part of food processing and packaging systems. They allow you to control your production more efficiently by providing motion to the machines at required speeds. In addition to this, they help in eliminating potentially harmful fluid-powered systems from the food production environment. Vowing their uses, electric actuators are widely used in the following areas: 

          • Conveyor Process
          • Bread Robots
          • Packaging Robotics
          • Ergonomic Stations

4.1.1: Benefits of Electric Actuators in the Food Industry:

Electric actuators offer various advantages for many industries, and the food industry is one of those. They are designed to perform in a rough and challenging environment. Here are a few benefits:

          • Speed up Operations
          • No Fluid Leakage
          • Hygienic Design
          • Corrosion resistance
          • Clean and Robust Actuator Technology


4.1.2: Disadvantage of Electric Actuators in the Food Industry:

Apart from various advantages, Electric actuators have a few disadvantages too:

          • lower speed than pneumatic and hydraulic actuators
          • less suitable for very heavy loads

      • Pneumatic Actuators: 

Pneumatic actuators are found in automated systems and machinery in every industry and come in a wide range of sizes, styles, and designs. Easy to maintain, they can operate at high speeds, offering tremendous flexibility and value for a seemingly endless number of applications. In addition to being fast, economical, and reliable, pneumatic actuators are also cleaner and safer than other solutions, which make them ideal for manufacturing, packaging, palletizing, material handling, food, and beverage, and many more applications.

Pneumatic actuators are devices that use compressed air to power motion. That motion can be along a rotational or linear path, ultimately assisting or performing a task such as pushing, pulling, gripping, turning, feeding, ejecting, opening, closing, holding, stopping, clamping, stamping, and, as you can guess, the list goes on. The forces that these actuators can produce depend primarily on the cylinder bore size (piston diameter) and the operating pressure, but rod size is also a very important consideration on the rod-style cylinder. 

  1. Transducers: 

A transducer can be anything that converts one form of energy to another. transducers that are used in food industries are piezoelectric, but some are magnetostrictive also. Piezoelectric transducers convert cyclic electrical current into physical vibrations, and magnetostrictive devices convert varying magnetic fields into physical vibrations.

5.1 Piezoelectric Transducer: 

A piezoelectric transducer (also known as a piezoelectric sensor) is a device that uses the piezoelectric effect to measure changes in acceleration, pressure, strain, temperature, or force by converting this energy into an electrical charge. The word piezoelectric is derived from the Greek word piezen, which means to squeeze or press. The piezoelectric effect states that when mechanical stress or forces are applied to a quartz crystal, produces electrical charges on the quartz crystal surface. The rate of charge produced will be proportional to the rate of change of mechanical stress applied to it. Higher will be stress, higher will be voltage.     

5.2 Magneto-strictive Transducer: 

A magnetostrictive transducer makes use of a type of magnetic material in which an applied oscillating magnetic field squeezes the atoms of the material together, creating a periodic change in the length of the material and thus producing a high-frequency mechanical vibration. Magnetostrictive transducers are used primarily in the lower frequency ranges and are common in ultrasonic cleaners and ultrasonic machining application 

  1. Reference: 

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